Techniques for quantum dot illumination

ABSTRACT

Techniques for extracting light from a light guide are described. In some embodiments, a light source comprises a light guide configured to trap first light through total internal reflection. The light source may further comprise a plurality of light extractors configured to extract at least a portion of the first light upon establishing optical contact with the light guide. The light source is configured to control individual light extractors in the plurality of light extractors to make optical contact with the light guide. Quantum dots may be used with the light source to regenerate light, within desired frequency band, from the at least a portion of the first light.

CROSS-REFERENCE TO RELATED APPLICATIONS

This Application claims benefit as a continuation of U.S. patentapplication Ser. No. 13/325,323 filed on Dec. 14, 2011, which in turnclaims benefit of priority to U.S. Provisional Patent Application No.61/424,199 filed on Dec. 17, 2010; U.S. Provisional Patent ApplicationNo. 61/448,599 filed on Mar. 2, 2011; U.S. Provisional PatentApplication No. 61/486,160 filed on May 13, 2011; U.S. ProvisionalPatent Application No. 61/486,166 filed on May 13, 2011; and U.S.Provisional Patent Application No. 61/486,171 filed on May 13, 2011,which are hereby incorporated herein by reference for all purposes as iffully set forth herein. The applicant(s) hereby rescind any disclaimerof claim scope in the parent applications or the prosecution historythereof and advise the USPTO that the claims in this application may bebroader than any claim in the parent applications.

TECHNOLOGY

The present invention relates generally to display systems, and inparticular, to quantum dots in display systems.

BACKGROUND

A display system may contain light valves (e.g., LCD) and color filters(e.g., imparting red, green and blue colors in a RGB system) thatregulate brightness levels and color values of pixels as the pixels arebeing illuminated by a light source, such as back light units (BLUs).Typically, light sources such as fluorescent lights or light-emittingdiodes (LEDs) illuminate pixels on display panels. The lightilluminating the pixels is attenuated by RGB color filters and liquidcrystal materials.

Engineering wide color gamut and high luminance has been recognized as avery difficult endeavor by many display manufactures. It is difficultfor a pixel or subpixel in a display system to accurately expressaccurate luminance values and color information. For example, light withdifferent colors and luminance levels may bleed into a portion of adisplay panel from neighboring portions of the display panel.

Further, different types of light emitters emit light of broad ranges ofwavelengths for which display systems are not optimized, imageinversions, restrictive viewing angles and undesirable colorrepresentations and tinges may occur in the display systems so thatdisplayed images suffer from poor quality or a limited color gamut.

The approaches described in this section are approaches that could bepursued, but not necessarily approaches that have been previouslyconceived or pursued. Therefore, unless otherwise indicated, it shouldnot be assumed that any of the approaches described in this sectionqualify as prior art merely by virtue of their inclusion in thissection. Similarly, issues identified with respect to one or moreapproaches should not assume to have been recognized in any prior art onthe basis of this section, unless otherwise indicated.

BRIEF DESCRIPTION OF DRAWINGS

The present invention is illustrated by way of example, and not by wayof limitation, in the figures of the accompanying drawings and in whichlike reference numerals refer to similar elements and in which:

FIG. 1A illustrates an example display system, according to anembodiment of the invention;

FIG. 1B illustrates an example light source comprising a light injector,a light guide, and a plurality of light extractors, in accordance withsome possible embodiments of the present invention;

FIG. 2A illustrates an example operation of optical contact between anindividual light extractor in a plurality of light extractors and alight guide which receives light from a light injector, in accordancewith some possible embodiments of the present invention;

FIG. 2B and FIG. 2C illustrate an example operation of optical contactbetween an individual light extractor in a plurality of light extractorsand a portion of a light guide, in accordance with some possibleembodiments of the present invention;

FIG. 2D illustrates an example light guide made up of non-contiguouslight guide strips separated by inter-strip gaps, in accordance withsome possible embodiments of the present invention;

FIG. 3A illustrates an example light extractor among a plurality oflight extractors around which mixed primary color quantum dots aredisposed, in accordance with some possible embodiments of the presentinvention;

FIG. 3B illustrates an example group of light extractors among aplurality of light extractors, in accordance with some possibleembodiments of the present invention;

FIG. 3C illustrates an example group of light extractors among aplurality of light extractors, in accordance with some possibleembodiments of the present invention;

FIG. 3D and FIG. 3E illustrate a triangular pattern and a linear patternamong many possible examples of top view patterns formed by single colorquantum dots, in accordance with some possible embodiments of thepresent invention;

FIG. 4A illustrates an example configuration in which two or moredistinct sets of quantum dots disposed with a plurality of lightextractors and a light guide, in accordance with some possibleembodiments of the present invention;

FIG. 4B illustrates an example configuration in which two or moredistinct sets of quantum dots disposed with a plurality of lightextractors and a light guide, in accordance with some possibleembodiments of the present invention;

FIG. 5 illustrates an example configuration of a display system thatcomprises display logic, in accordance with some possible embodiments ofthe present invention;

FIG. 6 illustrates an example process flow, according to a possibleembodiment; and

FIG. 7 illustrates an example hardware platform on which a computer or acomputing device as described herein may be implemented, according apossible embodiment of the present invention.

DESCRIPTION OF EXAMPLE POSSIBLE EMBODIMENTS

Example possible embodiments, which relate to quantum dot light sources,are described herein. In the following description, for the purposes ofexplanation, numerous specific details are set forth in order to providea thorough understanding of the present invention. It will be apparent,however, that the present invention may be practiced without thesespecific details. In other instances, well-known structures and devicesare not described in exhaustive detail, in order to avoid unnecessarilyoccluding, obscuring, or obfuscating the present invention.

Example embodiments are described herein according to the followingoutline:

-   1. General Overview-   2. Structure Overview-   3. Example Light Source-   4. Operation Related to Optical Contact-   5. Light Extractors-   6. 3D Display Applications-   7. Light Source Control Logic-   8. Example Process Flow-   9. Implementation Mechanisms—Hardware Overview-   10. Equivalents, Extensions, Alternatives and Miscellaneous

1. General Overview

This overview presents a basic description of some aspects of a possibleembodiment of the present invention. It should be noted that thisoverview is not an extensive or exhaustive summary of aspects of thepossible embodiment. Moreover, it should be noted that this overview isnot intended to be understood as identifying any particularlysignificant aspects or elements of the possible embodiment, nor asdelineating any scope of the possible embodiment in particular, nor theinvention in general. This overview merely presents some concepts thatrelate to the example possible embodiment in a condensed and simplifiedformat, and should be understood as merely a conceptual prelude to amore detailed description of example possible embodiments that followsbelow.

In some possible embodiments, a light source comprising a plurality oflight extractors and a light guide may be configured in a system. Eachlight extractor may be assigned to provide illumination on a portion ofa first surface of a layer outside the light source. For example, thelight source may be used in a display system to illuminate a light valvelayer which may be an optical layer that modulates light output torender images in various levels of resolutions. In some embodiments, thelight source may directly render images without other light modulationlayers that modulate light output on an individual pixel basis.

In some embodiments, the light guide may form a first part of the lightsource receiving and trapping first light emitted by light emitters(e.g., in a side light unit). The light extractors may form a secondpart of the light source and may be disposed adjacent to a surface(e.g., bottom surface; away from a viewer at the top) of the lightguide. Possible embodiments include light sources that are configured tomove only individual portions of the light guide, to move onlyindividual light extractors, or to move both individual portions of thelight guide and individual light extractors in a cooperative manner tocreate or to remove optical contacts between the light extractors andthe light guide.

In some embodiments, when no optical contacts are made with lightextractors, the light guide confines first light from light emitters(such as side light unit comprising LEDs) within the light guide throughtotal internal reflection. Under techniques described herein, lightotherwise trapped in the light guide is extracted through an opticalcontact between the light guide and a light extractor.

In some embodiments, first light injected into the light guide may beemitted by UV, blue, quantum dot rails, quantum dot strips, or otherlight emitters. In some embodiments, the system, or the light sourcetherein, is configured to control each optical contact between lightextractors and the light guide on an individual basis. The motion of alight extractor or a portion of the light guide may be effectuated withpneumatic force, mechanical force, gravitational force, orelectromagnetic field-based force.

For example, in a display system, when no image is to be displayed, thelight extractors and the light guide may have no or little opticalcontact. Thus, no or little light comes out of the light guide, or thelight source. On the other hand, when the display system is to render animage, relatively bright areas of the image as rendered by the lightvalve layer may be illuminated with relatively strong light, whilerelatively dim areas of the image may be illuminated with relativelyweak light. In a relatively bright area, a relatively large number ofoptical contacts may be established between the light extractors andlight guide. On the other hand, in a relatively dim area, a relativelysmall number of optical contacts may be established between the lightextractors and light guide. Other ways of controlling the intensity ofextracted light may be used in place of or in conjunction with thetechniques described herein. For example, time durations of opticalcontacts may be controlled so that a relatively bright area of an imageto be rendered corresponds to a relatively long time duration of opticalcontacts and a relatively dim area of an image to be renderedcorresponds to a relatively short time duration of optical contacts.

The ability of a light extractor described herein to extract light maybe configured through a relationship between refractive indexes of theoptical materials used in making the light guide and the lightextractor. For example, in the vicinity of an optical contact betweenthe light guide and the light extractor, the refractive indexes of thelight guide and the light extractor may be configured to cause arelatively large refraction/transmission rather than a reflection. Insome embodiments, in the vicinity of an optical contact, the refractiveindex of the light guide is much closer to the refractive index of thelight extractor than to the refractive index of air or vacuum. Theability of a light extractor described herein to extract light may beenhanced by other properties of the light guide (e.g., a conic structureor another structure with a bottom mirror surface) and the lightextractor.

The light guide and/or the layer comprising the light extractors may ormay not form a contiguous, non-perforating surface. In some embodiments,the light guide and/or the layer comprising the light extractors maycomprise at least two disjoint geometric shapes separated by anintershape gap. As used herein, a gap may refer to a spatial void or aspace filled with air or other types of materials that are differentfrom that of disjoint geometric shapes separated by the gap. For thepurpose of the present invention, other discrete or non-discrete,perforated or non-perforated, curved or non-curved, regular or irregularshapes may be used to carry/host portions of the light guide and/or thelight extractors.

In some embodiments, the light extracted from the light guide may beused to provide illumination to other components outside the lightsource. In some other embodiments, quantum dots may be deposited aroundoptical contacts as described herein to generate second light usingextracted light. The light source may be configured to provideillumination to other components outside the light source with thesecond light, instead of, or in addition to, any extracted first light.

In various possible embodiments, quantum dots may be disposed with thelight guide and the light extractors in various possible ways. Forexample, quantum dots may be coated on a top surface, a bottom surface,or both top and bottom surfaces of the light guide. Quantum dots alsomay be embedded within the light guide. Similarly, quantum dots may becoated on a top surface, a bottom surface, or both top and bottomsurfaces of a light extractor. Additionally and/or alternatively,quantum dots may be disposed with the light guide or the light extractorthrough a film, a sheet, etc., that is disposed near or at the lightguide or the light extractors.

Quantum dots may also be distributed in an unmixed pattern or in a mixedform. In some embodiments, quantum dots distributed in a mixed form maygenerate a relatively white light (which may be related to D65 underRec. 709, or D50 under P3, or another standard-based ornon-standard-based white point). In some other embodiments, quantum dotsdistributed in an unmixed pattern may generate separate primary colorswhich may be used to support a wide range of colors in a color gamut orto support specific colors (e.g., highly saturated colors that aredifficult to accomplish with white light).

In some embodiments, quantum dots may be relatively uniformlydistributed. In some other embodiments, quantum dots may form groups oflinear or non-linear patterns (e.g., arranged in a layer in a triangularpattern).

A light source described herein may or may not be a part of a displaysystem. In embodiments in which the light source is used with a displaysystem, additionally and/or optionally, a distinct set of quantum dotswith all the primary colors to support rendering color images in a colorspace may be used to create a left image, while another distinct set ofquantum dots with all the primary colors to support rendering colorimages in the color space may be used to create a right image. Thequantum dots in the two distinct sets may be so configured that lightwavelengths produced by one distinct set of quantum dots have no orlittle overlap with light wavelengths produced by the other distinct setof quantum dots. Passive 3D glasses may be used with the display systemto view these images in 3D display applications. For example, the leftperspective of the 3D glasses may be configured to transmit only thelight wavelengths in the left image, while the right perspective of the3D glasses may be configured to transmit only the light wavelengths inthe right image. Thus, under techniques described herein, costly activesynchronization between 3D glasses and image rendering may be avoided.

In some embodiments, a display system comprising a light sourcedescribed herein may further comprise light source control logicconfigured to determine, based on image data, which light extractors areto be in optical contact with the light guide. Additionally and/oroptionally, the display system may comprise sampling logic configured toestimate desired illumination on a portion of a plane based on pixelvalues in image data.

In some embodiments, a method comprises providing a light sourcedescribed herein in a display system.

In some possible embodiments, mechanisms as described herein form a partof a display system, including, but not limited to: a handheld device,game machine, television, laptop computer, netbook computer, cellularradiotelephone, electronic book reader, point of sale terminal, desktopcomputer, computer workstation, computer kiosk, PDA, various other kindsof terminals and display units, etc.

Various modifications to the preferred embodiments and the genericprinciples and features described herein will be readily apparent tothose skilled in the art. Thus, the disclosure is not intended to belimited to the embodiments shown, but is to be accorded the widest scopeconsistent with the principles and features described herein.

2. Structure Overview

FIG. 1A illustrates an example display system 100, according to anembodiment of the invention. Display system 100 comprises a light source102. Light source 102 may comprise an optical system comprising one ormore mirrors, lenses or other optical elements which cooperate todeliver light to the rest of display system 100.

In the illustrated embodiment, light from light source 102 is directedtoward a light valve layer 104. Light source 102 may provide a lightillumination field on light valve layer 104. A light illumination fielddescribed herein refers to a spatial power distribution of light; thespatial power distribution is controlled under techniques describedherein, for example, based on image data for one or more images that arebeing rendered by the display system. Light valve layer 104 comprises anarray of individually addressable light valves. Light valve layer 104may comprise, for example, a liquid crystal display (LCD) layer. Displaydriver circuitry or control logic (not shown in FIG. 1) controlsindividual light valves of light valve layer 104 according to image datawhich defines one or more images being rendered.

In some possible embodiments, display system 100 may comprise furtheroptical, electrical, or mechanical elements including one or moreadditional light valve layers with the same or different spatialresolutions, processors, controllers, data communication interfaces,software components, etc. For example, display system 100 may comprise adiffuser and/or a collimator configured to cause light to be relativelyevenly distributed in (e.g., relatively flattened light intensity withrelatively sharp falloffs beyond) a local spatial area and to travelthrough light valves in the light valve layer 104 in a direction whichis generally normal (e.g., perpendicular) to a viewer facing a surface(e.g., the top surface of light valve layer 104) of display system 100.

Display system 100 may be a color display system. This may be achievedin various ways including: making light valves in light valve layer 104color light valves; providing a plurality of different light valvesoperating in parallel on different colors; providing dye-based only,quantum-dot-based only, part dye/part quantum-dot-based color filters inthe light path of a light valve, etc.

In some possible embodiments, a display panel (e.g., an LCD type) has aplurality of pixels each comprising a number of colored sub-pixels. Forexample, using a red green blue (RGB) color space, each pixel maycomprise three sub-pixels, one associated with a red filter, oneassociated with a green filter and one associated with a blue filter. Acolor filter described herein may be embedded, coated, deposited, orother disposed with a light valve.

3. Example Light Source

FIG. 1B illustrates an example light source (e.g., 102) comprising alight injector (e.g., 106), a light guide (e.g., 110), and a pluralityof light extractors (e.g., 108), in accordance with some possibleembodiments of the present invention. A plurality of light extractors ina light source as described herein may be arranged in a geometric shapesuch as a rectangle as illustrated. Another geometric shape such asellipse, triangle, quadrilateral, etc., or a combination thereof, mayalso be used to arrange the light extractors on any of the displaypanels described herein.

In some embodiments, light injector (106) may be provided in the form ofa plurality of light emitting diodes (LEDs). In some embodiments, lightinjector (106) may be provided in the form of a quantum dot strip orrail that converts/regenerates light when illuminated by other visibleor invisible light with light wavelengths in one or more configuredranges of light wavelengths. Other types of light injectors may include,but are not limited only to, fluorescent light emitters, halogen lightemitters, etc.

Light guide (110) may be configured to receive light injected by lightinjector (106) and to keep light within light guide (110) until light isredirected towards light valve layer by one or more light extractorsamong the plurality of light extractors (108). As used herein, a lightguide (e.g., 110) may be an optical structure (e.g., a waveguide, aplate, a substrate, etc.) that comprises substantially reflectivesurfaces for injected light when not contacted by light extractors. Insome embodiments, the substantially reflective surfaces may be providedby (e.g., metallic or non-metallic) reflectors. In some embodiments, thesubstantially reflective surfaces may come about at a surface of thelight guide (110) because of the difference between refractive indexesinside and outside the light guide (110). In some embodiments, lightguide (110) may comprise one or more reflectors such as enhancedspecular reflectors (ESR). Additionally and/or optionally, undertechniques described herein, one, two or more ways of trapping lightwithin a light guide (110) may be used together at the same time.

In some embodiments, a light extractor described herein is configured toextract a portion of trapped light from light guide (110) and toredirect the extracted light towards light valve layer (104). In someembodiments, a light extractor described herein is configured togenerate second light from the extracted portion of light, and to directthe second light toward light valve layer (104). In these embodiments,the second light may be generated by quantum dots, quantum wells, oranother suitable light regeneration/conversion material.

In some embodiments, an individual light extractor and/or a light guide(e.g., 110) may be controlled by a display system (e.g., 100), or lightsource (102) therein, to make or not to make optical contact between theindividual light extractor and light guide (110). Upon optical contactbetween light guide (110) and a light extractor in the plurality oflight extractors (108), a portion of light may be extracted from lightguide (110). For example, a light extractor described herein may be madeof an optical material with a refractive index that causes the area ofcontact to be no longer total reflective.

In various embodiments, the optical contact of one or more lightextractor with light guide (110) may be controlled based at least inpart on a local luminance value such as an average luminance value, amaximum luminance value, etc., calculated for a subset of pixels in animage frame that is being rendered, wherein pixel values of the subsetof pixels are to be rendered by modulated light transmitted through asubset of light valves and wherein the subset of light valves areilluminated by the redirected light extracted by the one or more lightextractors.

In some embodiments, a light extractor and/or a light guide describedherein is movable. The motion of a light extractor and/or a light guidemay be effectuated with one or more mechanical, electro-magnetic, orgravitational forces. In an example, pressure from air or a lever may beused to cause the motion of a light extractor to make or not to makeoptical contact with light guide (110). In another example, a lightextractor may carry an electric or magnetic charge that may be acted onby an electromagnetic field to cause the motion of the light extractor.Alternatively and/or additionally, pressure from air or a lever,electromagnetic field, etc. may be used to cause the motion of a portionof a light guide (e.g., 110) to make or not to make optical contact withan individual light extractor.

4. Operation Related to Optical Contact

FIG. 2A illustrates an example operation of optical contact between anindividual light extractor (e.g., 108-1) in a plurality of lightextractors (e.g., 108) and a light guide (e.g., 110) which receiveslight (202) from a light injector (e.g., 106), in accordance with somepossible embodiments of the present invention. In some possibleembodiments, the light injector may be a side light unit (SLU). Invarious embodiments, light extracted by the light extractors (108) fromthe light guide (110) or light regenerated at or near optical contactsbetween the light guide (110) and the light extractors (108) may be usedas a light source, or may alternatively directly render images withoutother light modulation layers that modulate light output on anindividual pixel basis.

The plurality of light extractors (108) such as cones, prisms,triangular shapes, rectangular shapes, etc., may be disposed near lightguide (110). Each of the light extractors may be individually controlledto make contact with light guide (110). Light from the SLU may be of arelatively oblique angle and may be substantially (e.g., 95%, 98%, oranother percentile) trapped inside light guide (110) by total internalreflection. Upon touching light guide (110) by a light extractor (e.g.,108-1), a portion of the light, otherwise trapped, may be extractedthrough the contacting tip portion of the light extractor (108-1). Theoptical shape and properties of the light extractor (108-1) may bedesigned so as to reflect the extracted light toward a viewer (or alight valve layer such as LCD). Because the incidental angle of thereflected light from the light extractor (108-1) is no longer oblique,the light from the light extractor (108-1) may pass through light guide(110). In some possible embodiments, techniques described herein may beused to provide support for local dimming in which individual portions(each comprising a subset of pixels) of a light valve layer (e.g., 104)may be differently illuminated based on image data that is beingrendered in the individual portions of the light valve layer (104).

In some possible embodiments, a force (206) may be applied to anindividual light extractor (such as 108-1) to cause an optical contactbetween the individual light extractor (108-1) and light guide (110). Anindividual light extractor (e.g., 108-1) may be controlled withmechanical or electromagnetic force. For example, a push pin, amechanical device, air pressure or inductive electrical force may beexerted to cause a light extractor to move and make or not make contactwith another surface such as a surface of a light guide (e.g., 110). Asa result of the optical contact, second light (204) may be emittedtoward a light valve layer (e.g., 104 of FIG. 1A) and further toward aviewer (located at the top of FIG. 2A looking toward light guide).

Under techniques described herein, quantum dots may be disposed with alight extractor and/or a light guide and/or an SLU or BLU. In anexample, quantum dots may be coated or embedded with light guide (110).Additionally and/or alternatively, quantum dots may be coated orembedded with some or all light extractors (108). Additionally and/oralternatively, quantum dots may be disposed with light extractors (108)and/or light guide (110) using a quantum dot film, a quantum dot sheet,a quantum dot substrate, etc.

FIG. 2B and FIG. 2C illustrate an example operation of optical contactbetween an individual light extractor (e.g., 108-2) in a plurality oflight extractors (e.g., 108 of FIG. 1B) and a portion (110-1) of a lightguide (e.g., 110), in accordance with some possible embodiments of thepresent invention. In various embodiments, light extracted by the lightextractors (108) from the light guide (110) or light regenerated at ornear optical contacts between the light guide (110) and the lightextractors (108) may be used as a light source, or may alternativelydirectly render images without other light modulation layers thatmodulate light output on an individual pixel basis. In some possibleembodiments, as illustrated in FIG. 2B and FIG. 2C, the light extractors(108) may be placed above the light guide (110), instead of below alight guide as illustrated in FIG. 2A. In some possible embodiments, asillustrated in FIG. 2B and FIG. 2C, portions of the light guide (110)may be controlled to move, relative to the light extractors, to make ornot to make contact with individual light extractors. As illustrated inFIG. 2B, the portion (110-1) of the light guide (110) may be moved to afirst position that makes no contact with the individual light extractor(108-2); the first position may be the natural position of the portion(110-1) when no force is exerted. In contrast, as illustrated in FIG.2C, the portion (110-1) of the light guide (110) may be moved to asecond position that makes contact with the individual light extractor(108-2); the second position may be a position of the portion (110-1)when a force (e.g., static, pneumatic, etc.) is exerted. When theindividual light extractor (108-2) makes contact with the light guide(110), second light (204) may be produced from trapped light (202) toilluminate a light valve layer (e.g., 104).

For the purpose of illustration, it has been illustrated that a lightguide may be contiguous and non-perforated, while a plurality of lightextractors may be individual discrete shapes arranged in a lattice ormatrix. It should be noted that the present invention is not so limited.In an example embodiment, as illustrated in FIG. 2D, a light guide maybe made up of non-contiguous light guide strips separated by inter-stripgaps. Alternatively and/or optionally, light extractors may be providedwith shapes other than discrete shapes in a lattice of matrix. Forexample, as illustrated in FIG. 2D, light extractors may be embeddedwith light redirecting strips crossing the light guide strips. Crossedportions may be configured to be statically attracted to each other toproduce light extraction. Quantum dots (QD; e.g., mixed RGB quantumdots, or individual R, G or B quantum dots) may be disposed with thelight guide and/or the light extractors (e.g., on one or more surfacesof the light guide and/or the light extractors). In this example, theplurality of light extractors (108) may refer to a plurality of portionsof the light redirecting strips with which portions the light guide areconfigured to make contact. Therefore, these and other ways ofconfiguring light extractors are within the scope of the presentinvention.

5. Light Extractors

FIG. 3A illustrates an example light extractor (e.g., 108-3) among aplurality of light extractors (e.g., 108 of FIG. 1B) around which mixedprimary color quantum dots are disposed, in accordance with somepossible embodiments of the present invention. In some possibleembodiments, a display system described herein may support a color spacecomprising three or more primary colors (e.g., R, G and B as primarycolors). Each of the three or more primary colors may be emitted by adifferent group in three or more groups of quantum dots. In somepossible embodiments, at or near a light extractor (e.g., 108-3),quantum dots from two or more groups of the three or more groups may bemixed. In an example, quantum dots at or near a light extractor (108-3)may comprise RGB quantum dots. The composition of the mixed quantum dotsmay be configured to provide a white point. The white point may be D65under Rec. 709, D50 under P3,or another type of white point (includingbut not limited to a standard-based or non-standard-based white point).The portion of second light produced with first light from a SLU (e.g.,106) upon optical contact between the light extractor (108-3) and aportion of a light guide (e.g., 110) may be configured to illuminate aportion (e.g., 204-1) of a light valve layer (104). In some embodiments,the portion of second light may be configured as a part of substantiallyuniform illumination on the light valve layer (104). In some otherembodiments, second light from the light extractors (108) may beconfigured to support local dimming. For example, the portion (204-1;comprising a subset of pixels) of the light valve layer (104) may bedifferently illuminated, relative to other portions (or pixels) of thelight valve layer (104), based on image data that is being rendered inthe portion of the light valve layer (104). In various embodiments,light extracted by the light extractors (108) from the light guide (110)or light regenerated at or near optical contacts between the light guide(110) and the light extractors (108) may be used as a light source, ormay alternatively directly render images without other light modulationlayers that modulate light output on an individual pixel basis.

FIG. 3B illustrates an example group of light extractors (e.g., 108-4,108-5 and 108-6) among a plurality of light extractors (e.g., 108 ofFIG. 1B), in accordance with some possible embodiments of the presentinvention. In an example display system that supports a RGB color space,quantum dots around or with a light extractor (108-4, 108-5, or 108-6)may comprise single color quantum dots (e.g., green, red, or bluequantum dots). The portion of second light produced upon optical contactbetween the light extractor (108-4) and a portion of a light guide(e.g., 110) may be configured to illuminate a portion (204-2) of a lightvalve layer (104) with a particular color (e.g., green). The portion ofsecond light produced upon optical contact between the light extractor(108-5) and the light guide (110) may be configured to illuminate theportion (204-2) of the light valve layer (104) with a second differentcolor (e.g., blue). The portion of second light produced upon opticalcontact between the light extractor (108-6) and the light guide (110)may be configured to illuminate the portion (204-2) of a light valvelayer (104) with a third different color (e.g., red). In some possibleembodiments, optical components such as diffusers, collimators,reflectors, mirrors, bumpy metallic surfaces, etc. may be used undertechniques herein to direct illumination from each light extractor of agroup of light extractors (108-4, 108-5, and 108-6) to the same portion(204-2) of the light valve layer (104).

In some embodiments, second light produced by the light extractors (108)may be configured to provide substantially uniform illumination on thelight valve layer (104). In some other embodiments, second lightproduced by the light extractors (108) may be configured to supportlocal dimming for specific colors (e.g., red, green, and blue). Forexample, the portion (comprising a subset of pixels) of the light valvelayer (104) may be differently illuminated, relative to other portionsof the light valve layer (104), based on image data that is beingrendered in the portion of the light valve layer (104). Furthermore, theportion of the light valve layer (104) may be differently illuminatedfor a specific color (e.g., green), relative to other colors (e.g., redand blue), based on color specific image data that is being rendered inthe portion of the light valve layer (104).

In some embodiments, the intensity of each color may be regulated by thenumber of optical contacts between specific color light extractors andthe light guide (110). For example, the sampling of image data mayindicate that a maximum pixel value for a specific color (e.g., green)in the portion (204-2) of the light valve layer (104) may be 100. Alight source controller in the display system may calculate, based onthe maximum pixel value for the green color, how many light extractorsof a specific color (green in the present example) are needed to makeoptical contacts with the light guide (110) in order to provide anappropriate intensity of green light corresponding to the maximum pixelvalue for the green color.

In some embodiments, the intensity of each color may be regulated by atime duration of optical contact between a specific color lightextractor and the light guide (110). For example, the sampling of imagedata may indicate that a maximum pixel value for a specific color (e.g.,green) in the portion (204-2) of the light valve layer (104) may be 100.A light source controller in the display system may calculate, based onthe maximum pixel value for the green color, a time duration of opticalcontact between the green light extractor (108-4) and the light guide(110) in order to provide an appropriate intensity of green lightcorresponding to the maximum pixel value for the green color.

For the purpose of illustration, it has been described that the maximumpixel value for a specific color for a subset of pixels on a light valvelayer may be used to determine how many optical contacts and/or how longa time duration is. Other measures other than the maximum pixel valuemay be used in such determination. In various possible embodiments, adisplay system may be configured to use the average pixel value, 75% ofthe maximum value, 95% of the maximum value, twice the average pixelvalue, or another value computed based on image data, to determine thenumber of optical contacts and/or the length of a time duration herein.

In some embodiments, light extractors with other colors, in addition toprimary colors in the color space supported by the display system, maybe used to produce these other colors (e.g., saturated colors) in orderto support a wide color gamut.

In some possible embodiments, two (e.g., 108-4 and 108-5) or more lightextractors in a group of light extractors (e.g., 108-4, 108-5, and108-6) may have an overlapping time duration in which the two (108-4 and108-5 in the present example) or more light extractors concurrently makeoptical contacts with the light guide (110). In some possibleembodiments, no two light extractors in a group of light extractors mayhave an overlapping time duration. For example, different color lightmay provide illumination to the same portion (e.g., 204-2) of a lightvalve layer (104) in a time sequential manner.

It should be noted that, as illustrated in FIG. 2B and FIG. 2C, opticalcontacts as illustrated in FIG. 3A may be caused alternatively by movingportions of a light guide (110), instead of by moving light extractors.

In various possible embodiments, quantum dots (QD) described herein,whether of a single primary color or a mixture of primary colors, may bedisposed with the light guide (104) and/or the light extractor (108-3).In an example, at least a portion of the quantum dots may be disposed onone or more surfaces of the light guide (104) and/or the light extractor(108-3). In a particular embodiment, at least a portion of quantum dotsmay be located underneath, on, or above the viewer facing top surface ofthe light guide (104).

FIG. 3C illustrates an example group of light extractors (e.g., 108-4,108-5 and 108-6) among a plurality of light extractors (e.g., 108 ofFIG. 1B), in accordance with some possible embodiments of the presentinvention. In various embodiments, light extracted by the lightextractors (108) from the light guide (110) or light regenerated at ornear optical contacts between the light guide (110) and the lightextractors (108) may be used as a light source, or may alternativelydirectly render images without other light modulation layers thatmodulate light output on an individual pixel basis. Under techniquesdescribed herein, quantum dots may be distributed or disposed at or nearan optical contact area between a light extractor and a light guide. Forexample, quantum dots may be on a surface of the light guide, on asurface of the light extractor, on an opposing surface, of the lightextractor or light guide, away from the optical contact area, in theinterior of the light extractor or light guide, etc.

In an example display system that supports a RGB color space, quantumdots may be coated or otherwise disposed in contact areas (e.g., 302-1,302-2 and 302-3), on a surface of a light guide (110), with lightextractor (108-4, 108-5 and 108-6, respectively, in the presentexample). Each of the contact areas (e.g., each of 302-1, 302-2 and302-3) may comprise single color quantum dots (e.g., green, red, or bluequantum dots). The portion of second light produced upon optical contactbetween the light extractor (108-4) and a portion of a light guide(e.g., 110) may be configured to illuminate a portion (204-2) of a lightvalve layer (104) with a particular color (e.g., green).

In some embodiments, single color quantum dots of other colors, inaddition to primary colors in the color space supported by the displaysystem, may be disposed with or on the surface of a light guide toproduce these other colors (e.g., saturated colors) in order to supporta wide color gamut.

FIG. 3D and FIG. 3E illustrate a triangular pattern and a linear patternamong many possible examples of top view patterns formed by single colorquantum dots, in accordance with some possible embodiments of thepresent invention. In various embodiments, light extracted orregenerated with these patterns may be used as a light source, or mayalternatively directly render images without other light modulationlayers that modulate light output on an individual pixel basis. Eachcircle in FIG. 3D and FIG. 3E represents an individual distributionaround an optical contact area between a light extractor and a lightguide. As used herein, a subset of contact areas refers to a collectionof contact areas that emit second light to illuminate a common imageportion (a pixel, a pixel block, a subset of pixels etc. in an imageframe), wherein each individual contact area in the subset of contactareas may emit a different color light. For example, contact area 302-1in a subset of contact areas may emit a green light, contact area 302-2in the same subset may emit a red light, and contact area 302-3 in thesame subset may emit a blue light, as determined by the types of quantumdots disposed near or at these individual contact areas, respectively.In some embodiments, individual contact areas in the same subset mayemit light in a time-wise sequential manner. In some embodiments,individual contact areas in the same subset may emit light in one ormore partially or completely overlapping time intervals together. Insome embodiments, whether individual contact areas emit light inoverlapping time intervals or not, the intensities of different colorlights emitted by individual contact areas in the subset may beindividually and independently controlled. For example, the intensity ofthe green light from contact area 302-1 may be controlled/regulated bythe time duration in which the optical contact is maintained at contactarea 302-1 between a portion of a light guide and a corresponding lightextractor. The intensity of different color lights from differentcontact areas (e.g., 302-2 and 302-3) in a subset may becontrolled/regulated (e.g., at the same time) to different values otherthan what is set for the green light, or in alternative embodiments tothe same value as that of the green light. Light intensity may becontrolled on a larger scale than an image portion illuminated by asubset of contact areas. For example, in some embodiments, by varyingtime durations of optical contacts for contact areas that illuminate animage area corresponding to more than one subset of contact areas, thelight intensity on the image area may also vary. Additionally and/oralternatively, by varying the number (e.g., all, some, or none) ofoptical contacts for contact areas that illuminate an image areacorresponding to more than one subset of contact areas, the lightintensity on the image area may also vary. Additionally and/oralternatively, by varying concentrations of different types of quantumdots at or near a subset of contact areas, the light intensity on theimage area for a color component may also vary.

6. 3D Display Applications

FIG. 4A illustrates an example configuration in which two or moredistinct sets of quantum dots disposed with a plurality of lightextractors (e.g., 108 of FIG. 1B) and a light guide, in accordance withsome possible embodiments of the present invention. In variousembodiments, light extracted or regenerated with these patterns may beused as a light source, or may alternatively directly render imageswithout other light modulation layers that modulate light output on anindividual pixel basis. In some possible embodiments, each of the two ormore distinct sets of quantum dots may be configured to support allcolors in a color space in a display system described herein. In somepossible embodiments, a first set of quantum dots (R1G1B1 QD), among thetwo or more sets of quantum dots, may comprise at least three differentfirst primary colors; a second set of quantum dots (R1G1B1 QD), amongthe two or more sets of quantum dots, may also comprise at least threedifferent second primary colors. The first primary colors may, but arenot limited only to, be the same as the second primary colors, forexample, red, green and blue.

In some embodiments, first light wavelengths emitted by the first set ofquantum dots for a specific color may be different from second lightwavelengths emitted by the second set of quantum dots for the samespecific color. For example, the first light wavelengths may occupy arange of wavelengths different from that of the second lightwavelengths. In some embodiments, the first light wavelengths and thesecond light wavelengths have little or no common wavelengths. In someother embodiments, the first light wavelengths and the second lightwavelengths have some common wavelengths.

In some possible embodiments, quantum dots of different colors in eachdistinct set of quantum dots may be distributed or disposed in anunmixed pattern with each color at or near separate optical contactareas between the light extractors and the light guide. In some otherpossible embodiments, as illustrated in FIG. 4A, quantum dots ofdifferent colors in each distinct set of quantum dots may be mixed. Themixed quantum dots in the set are distributed or disposed near eachoptical contact area between the light extractors and the light guide.

In some possible embodiments, each distinct set of quantum dots mayindependently support a color space comprising three or more primarycolors (e.g., R, G and B as primary colors). In an example, quantum dotsaround a light extractor (108-3) may comprise RGB quantum dots. Thecomposition of the mixed quantum dots may be configured to provide awhite point. The white point may be D65 under Rec. 709, D50 under P3, oranother type of white point (including but not limited only to astandard-based or non-standard-based white point). Second light producedwith first light from a SLU (e.g., 106) upon optical contact between alight extractor (e.g., 108-7 or 108-8) and a portion of a light guide(e.g., 110) may be configured to illuminate a portion (204-3) of a lightvalve layer (104). In some embodiments, second light may be configuredas substantially uniform illumination on the light valve layer (104). Insome other embodiments, second light from the light extractors (108) maybe configured to support local dimming which illuminates differentportions of the light valve layer (104) differently, based on image databeing rendered in the different portions of the light valve layer (104).

In some possible embodiments, the first distinct set of quantum dotsthat independently supports the color space may be used to generate afirst image frame, while the second distinct set of quantum dots thatalso independently supports the color space may be used to generate asecond image frame. In some possible embodiments, the first distinct setof quantum dots emits in first relatively narrow wavelength ranges,while the second distinct set of quantum dots emits in second relativelynarrow wavelength ranges. The first relatively narrow wavelength rangesmay have no or little common wavelength with the second relativelynarrow wavelength ranges. The first image frame may be a left view imagein 3 dimensional (3D) display applications, while the second image framemay be a right view image in the 3D display applications. The firstimage frame and the second image frame may be generated in a time-wiseframe sequential manner. In some possible embodiments, a viewer may weara pair of glasses with a left perspective configured to be transmissivefor the first wavelength ranges but opaque for the second wavelengthranges, and with a right perspective configured to be transmissive forthe second wavelength ranges but opaque for the first wavelength ranges.Under techniques described herein, synchronization between a viewer'sglasses and an image rendering system such as a display system is notneeded in 3D display applications.

FIG. 4B illustrates an example configuration in which two or moredistinct sets of quantum dots disposed with a plurality of lightextractors (e.g., 108 of FIG. 1B) and a light guide, in accordance withsome possible embodiments of the present invention. In variousembodiments, light extracted or regenerated with these patterns may beused as a light source, or may alternatively directly render imageswithout other light modulation layers that modulate light output on anindividual pixel basis. In some possible embodiments, each of the two ormore distinct sets of quantum dots may be configured to independentlysupport all colors in a color space in a display system describedherein.

In some possible embodiments, as illustrated in FIG. 4B, quantum dots ofdifferent colors in each distinct set of quantum dots may be distributedor disposed in an unmixed pattern with each color at or near separateoptical contact areas between the light extractors and the light guide.Quantum dots disposed with a group of light extractors (e.g., 108-9through 14) may be optically configured to illuminate the same portion(204-4) of a light valve layer (104). For example, R1 quantum dots(e.g., configured to regenerate red light) may be disposed at or nearthe optical contact area between a light extractor 108-14 and the lightguide (110), while R2 quantum dots (e.g., also configured to regeneratered light, but in different light wavelengths than those of R1 quantumdots) may be disposed at or near the optical contact area between alight extractor 108-12 and the light guide (110). Similarly, G1 and B1quantum dots (e.g., configured to regenerate green light and blue light,respectively) may be disposed at or near the optical contact areasbetween light extractors 108-10 and 108-11, respectively, and the lightguide (110), while G2 and B2 quantum dots (e.g., configured toregenerate green light and blue light, respectively, but in differentlight wavelengths than those of G1 and B1) may be disposed at or nearthe optical contact areas between light extractors 108-9 and 108-13,respectively, and the light guide (110).

In some embodiments, light of all colors (e.g., R1, G1 and B1) producedby a distinct set (e.g., the first set) of quantum dots herein may beproduced concurrently. For example, in the same time interval, R1, G1and B1 may produce red, green and blue light concurrently. In some otherembodiments, light of different colors (e.g., R1, G1 or B1) in adistinct set (e.g., the first set) of quantum dots may be produced in atime-wise color sequential manner. For example, in a time-wise sequenceof light production, R1 may produce red light first, G1 may producegreen light next, and B1 may produce blue light last.

In some embodiments, two or more different sets (e.g., the first set andthe second set) of quantum dots described herein may produce secondlight of one, two or more colors concurrently. For example, in the sametime interval, R1 in the first set and R2 in the second set may producered light concurrently. In some other embodiments, at least two distinctset (e.g., the first set and the second set) of quantum dots may producesecond light in a time-wise color sequential manner. For example, in atime-wise sequence of light production, the first set of quantum dotsmay produce light first, and the second set of quantum dots may producelight next. In these embodiments, second light of specific colors may ormay not be concurrently produced by a distinct set (e.g., the first setor the second set) of quantum dots.

As in FIG. 4A, in FIG. 4B, the first distinct set of quantum dots thatindependently supports the color space may be used to generate a firstimage frame, while the second distinct set of quantum dots that alsoindependently supports the color space may be used to generate a secondimage frame. In some possible embodiments, the first distinct set ofquantum dots emits in first relatively narrow wavelength ranges, whilethe second distinct set of quantum dots emits in second relativelynarrow wavelength ranges. The first relatively narrow wavelength rangesmay have no or little common wavelength with the second relativelynarrow wavelength ranges. The first image frame may be a left view imagein 3 dimensional (3D) display applications, while the second image framemay be a right view image in the 3D display applications. The firstimage frame and the second image frame may be generated in a time-wiseframe sequential manner. In some possible embodiments, a viewer may weara pair of glasses with a left perspective configured to be transmissivefor the first wavelength ranges but opaque for the second wavelengthranges, and with a right perspective configured to be transmissive forthe second wavelength ranges but opaque for the first wavelength ranges.Under techniques described herein, synchronization between a viewer'sglasses and an image rendering system such as a display system is notneeded in 3D display applications.

7. Light Source Control Logic

FIG. 5 illustrates an example configuration of a display system (e.g.,100) that comprises display logic (502), in accordance with somepossible embodiments of the present invention. In some possibleembodiments, display logic 502 additionally and/or optionally maycomprise light source control logic (504) configured to controlcomponent in a light source (e.g., 102) in display system 100. Thedisplay logic 502 may be operatively coupled with an image data source506 (e.g., a set-top box, networked server, storage media or the like)and is configured to receive image data from the image data source 506.The image data may be provided by the image data source 506 in a varietyof ways including from an over-the-air broadcast, or Ethernet,High-Definition Multimedia Interface (HDMI), wireless network interface,devices (e.g., set-top box, server, storage medium), etc. Image framesreceived from an internal or external source may be used by the displaylogic 502 to drive a light valve layer (e.g., 104 of FIG. 1A) in displaysystem 100, and to drive light source 104 and components therein. Forexample, display logic 502 may be configured to control a subset oflight extractors to make contact with a light guide (e.g., 110 of FIG.1B) to produce second light illuminating some or all portions of thelight valve layer (104). The image frames may also be used by thedisplay logic 502 to derive individual or aggregate pixel values invarious frames in various resolutions to drive individual light sourcecomponents as described herein.

8. Example Process Flow

FIG. 6 illustrates an example process flow according to a possibleembodiment of the present invention. In some possible embodiments, oneor more computing devices or components in a display system (e.g., 500)comprising light source control logic (e.g., 504) and a light source(e.g., 102) may perform this process flow. In block 610, the displaysystem (100) confines first light (e.g., 202) within a light guide(e.g., 110) through internal reflection. The internal reflection may betotal internal reflection in some embodiments, or may be less than totalinternal reflection in some other embodiments. In some possibleembodiments, the light guide comprises one or more of acrylic resin,polycarbonate, epoxies, or glass.

In block 620, the display system (100) extracts at least a portion ofthe first light (202) from the light guide (110) upon establishingoptical contacts between the light guide (110) and one or more lightextractors (e.g., 108-1) in a plurality of light extractors (e.g., 108).Here, at least one (e.g., 108-1) of (a) individual light extractors inthe plurality of light extractors (108) or (b) portions (e.g., 110-1) ofthe light guide (110) is configured to be moved to cause an opticalcontact between a light extractor (e.g., 108-1) in the plurality oflight extractors (e.g., 108) and a portion (110-1) of the light guide(110). In various embodiments, light extracted or regenerated may beused as a light source, or may alternatively directly render imageswithout other light modulation layers that modulate light output on anindividual pixel basis.

In some embodiments, an optical contact herein is made by moving thelight extractor in the plurality of light extractors towards the portionof the light guide, or alternatively by moving the portion of the lightguide towards the light extractor in the plurality of light extractors.

In some embodiments, the light guide (110) comprises at least twogeometric shapes (210-1 and 210-2) separated by an inter-shape gap. Forthe purpose of the present invention, other discrete or non-discrete,perforated or non-perforated, curved or non-curved, regular or irregularshapes may be used to carry/host portions of the light guide (110).

As illustrated in FIG. 2D, in some possible embodiments, the pluralityof light extractors (108) comprises a first subset of light extractors(e.g., those on a first strip 208-1 of FIG. 2D) with a first geometricshape and a second subset of light extractors (e.g., those on a firststrip 208-2 of FIG. 2D) with a second geometric shape, and wherein thefirst geometric shape and the second geometric shape are separated by aninter-shape gap. For the purpose of the present invention, otherdiscrete or non-discrete, perforated or non-perforated, curved ornon-curved, regular or irregular shapes may be used to carry/host theplurality of light extractors (108).

As illustrated in FIG. 3D and FIG. 3E, in some embodiments, theplurality of light extractors (108) forms a plurality of groups (one ofwhich, for example, may be formed by 302-1, 302-2 and 302-3 of FIG. 3Dand FIG. 3E) of light extractors, and wherein light extractors in eachgroup in the plurality of groups of light extractors comprise two ormore light extractors (302-1, 302-2 and 302-3 of FIG. 3D and FIG. 3E)each with a different primary color. Each group in the plurality ofgroups of light extractors may be configured to illuminate a specificportion of a light valve layer. In some embodiments, each group in theplurality of groups of light extractors forms a linear pattern. In someembodiments, each group in the plurality of groups of light extractorsforms a non-linear pattern.

In some embodiments, the plurality of light extractors (108) compriseslight extractors for three or more mutually different primary colors.For example, some first light extractors may be configured to producered color, some second light extractors may be configured to producegreen color, and some light extractors may be configured to produce bluecolor. In some embodiments, more than four primary colors may be used.For example, in addition to the above-mentioned colors, some other lightextractors in the plurality of light extractors (108) may be configuredto produce light of yellow, cyan, or magenta color.

A light source described herein may or may not be a part of a displaysystem. In embodiments in which the light source is used with a displaysystem (e.g., 100) that supports rendering color images in a color space(e.g., a RGB color space), the plurality of light extractors (108)comprises two distinct sets (e.g., a first set of light extractors withR1G1B1 quantum dots, and a second set of light extractors with R2G2B2quantum dots) of light extractors, each set in the two distinct sets oflight extractors independently supporting the color space. A first setof light extractors (with R1G1B1 quantum dots) may be configured to beused in rendering a first image frame, while a second different set(with R2G2B2 quantum dots) in the two distinct sets of light extractorsmay be configured to be used in rendering a second different imageframe. Here, the first image frame and the second different image framemay be rendered time sequentially and may form a 3-dimensional (3D)image.

In some embodiments, first light (202) described herein comprises atleast one of invisible light or visible light. For example, at least aportion of the first light (202) may be visible blue light from blueLEDs. Alternatively and/or additionally, at least a portion of the firstlight (202) may be ultraviolet (UV) light.

In some embodiments, a portion of the first light (202) may be used togenerate a portion of second light (204) that illuminates a portion of alight valve layer. The first light and the second light have differentlight wavelength compositions. For example, the extracted first lightmay be used to excite quantum dots disposed around an optical contactarea between a light extractor and the light guide (110). The quantumdots in turn generate the second light (204) to illuminate a light valvelayer (104). The second light may be visible light (e.g., white lightwith D65, D50, or another standard-based or non-standard-based whitepoint).

In some embodiments, a portion of the first light (202) is extractedthrough one of the optical contacts, and after light extraction isdirectly used to illuminate a portion of a light valve layer (104).

In some embodiments, the light guide (110) is of a different refractiveindex than that of the light extractors (108), while in some otherembodiments, the light guide (110) is of a same refractive index as thatof the light extractors (108).

In some embodiments, a light extractor described herein may comprise oneof a prism or a cone. In some embodiments, a light extractor describedherein may be configured to redirect light towards a viewer facingsurface of the light guide.

Under techniques described herein, quantum dots may be configured with alight source described herein to convert the at least a portion of firstlight (202) to second light (204), wherein the second light (202)illuminates a portion of a light valve layer (104). In some possibleembodiments, at least a portion of the quantum dots is disposed with thelight guide. In some possible embodiments, at least a portion of thequantum dots is disposed with the light extractors. In some possibleembodiments, the quantum dots may be disposed with more than two opticalcomponents (e.g., the light extractors and the light guide).

In some embodiments, at least one light extractor in the plurality oflight extractors comprises a surface coated with quantum dots, orembedded with quantum dots. In some embodiments, at least one portion ofa light guide described herein comprises a surface area coated withquantum dots, or embedded with quantum dots.

In some embodiments, the light source is configured to exert on one ofan individual light extractor or a portion of the light guide throughone or more of pneumatic force, mechanical force, gravitational force,or electromagnetic field-based force.

In some embodiments, a light source described herein is configured as aback light unit in a display system. The display system may compriselight source control logic configured to determine, based on image data,which light extractors in the plurality of light extractors are to be inoptical contact with the light guide. Additionally and/or optionally,the display system may comprise sampling logic configured to estimatedesired illumination on a portion of a plane based on pixel values inimage data.

In some embodiments, different color components of the second lightilluminating an image portion of an image are individually controlledbased on image data of the image. For example, intensity of a colorcomponent in the different color components of the second lightilluminating the image portion is controlled by varying, based on theimage data, one or more of time durations of optical contacts at one ormore contact areas for the color component between the light guide andone or more corresponding light extractors, or number per unit area ofoptical contacts at one or more contact areas for the color componentbetween the light guide and the plurality of light extractors.

9. Implementation Mechanisms—Hardware Overview

According to one embodiment, the techniques described herein areimplemented by one or more special-purpose computing devices. Thespecial-purpose computing devices may be hard-wired to perform thetechniques, or may include digital electronic devices such as one ormore application-specific integrated circuits (ASICs) or fieldprogrammable gate arrays (FPGAs) that are persistently programmed toperform the techniques, or may include one or more general purposehardware processors programmed to perform the techniques pursuant toprogram instructions in firmware, memory, other storage, or acombination. Such special-purpose computing devices may also combinecustom hard-wired logic, ASICs, or FPGAs with custom programming toaccomplish the techniques. The special-purpose computing devices may bedesktop computer systems, portable computer systems, handheld devices,networking devices or any other device that incorporates hard-wiredand/or program logic to implement the techniques.

For example, FIG. 7 is a block diagram that illustrates a computersystem 700 upon which an embodiment of the invention may be implemented.Computer system 700 includes a bus 702 or other communication mechanismfor communicating information, and a hardware processor 704 coupled withbus 702 for processing information. Hardware processor 704 may be, forexample, a general purpose microprocessor.

Computer system 700 also includes a main memory 706, such as a randomaccess memory (RAM) or other dynamic storage device, coupled to bus 702for storing information and instructions to be executed by processor704. Main memory 706 also may be used for storing temporary variables orother intermediate information during execution of instructions to beexecuted by processor 704. Such instructions, when stored innon-transitory storage media accessible to processor 704, rendercomputer system 700 into a special-purpose machine that is customized toperform the operations specified in the instructions.

Computer system 700 further includes a read only memory (ROM) 708 orother static storage device coupled to bus 702 for storing staticinformation and instructions for processor 704. A storage device 710,such as a magnetic disk or optical disk, is provided and coupled to bus702 for storing information and instructions.

Computer system 700 may be coupled via bus 702 to a display 712, such asa liquid crystal display, for displaying information to a computer user.An input device 714, including alphanumeric and other keys, is coupledto bus 702 for communicating information and command selections toprocessor 704. Another type of user input device is cursor control 716,such as a mouse, a trackball, or cursor direction keys for communicatingdirection information and command selections to processor 704 and forcontrolling cursor movement on display 712. This input device typicallyhas two degrees of freedom in two axes, a first axis (e.g., x) and asecond axis (e.g., y), that allows the device to specify positions in aplane.

Computer system 700 may implement the techniques described herein usingcustomized hard-wired logic, one or more ASICs or FPGAs, firmware and/orprogram logic which in combination with the computer system causes orprograms computer system 700 to be a special-purpose machine. Accordingto one embodiment, the techniques herein are performed by computersystem 700 in response to processor 704 executing one or more sequencesof one or more instructions contained in main memory 706. Suchinstructions may be read into main memory 706 from another storagemedium, such as storage device 710. Execution of the sequences ofinstructions contained in main memory 706 causes processor 704 toperform the process steps described herein. In alternative embodiments,hard-wired circuitry may be used in place of or in combination withsoftware instructions.

The term “storage media” as used herein refers to any non-transitorymedia that store data and/or instructions that cause a machine tooperation in a specific fashion. Such storage media may comprisenon-volatile media and/or volatile media. Non-volatile media includes,for example, optical or magnetic disks, such as storage device 710.Volatile media includes dynamic memory, such as main memory 706. Commonforms of storage media include, for example, a floppy disk, a flexibledisk, hard disk, solid state drive, magnetic tape, or any other magneticdata storage medium, a CD-ROM, any other optical data storage medium,any physical medium with patterns of holes, a RAM, a PROM, and EPROM, aFLASH-EPROM, NVRAM, any other memory chip or cartridge.

Storage media is distinct from but may be used in conjunction withtransmission media. Transmission media participates in transferringinformation between storage media. For example, transmission mediaincludes coaxial cables, copper wire and fiber optics, including thewires that comprise bus 702. Transmission media can also take the formof acoustic or light waves, such as those generated during radio-waveand infra-red data communications.

Various forms of media may be involved in carrying one or more sequencesof one or more instructions to processor 704 for execution. For example,the instructions may initially be carried on a magnetic disk or solidstate drive of a remote computer. The remote computer can load theinstructions into its dynamic memory and send the instructions over atelephone line using a modem. A modem local to computer system 700 canreceive the data on the telephone line and use an infra-red transmitterto convert the data to an infra-red signal. An infra-red detector canreceive the data carried in the infra-red signal and appropriatecircuitry can place the data on bus 702. Bus 702 carries the data tomain memory 706, from which processor 704 retrieves and executes theinstructions. The instructions received by main memory 706 mayoptionally be stored on storage device 710 either before or afterexecution by processor 704.

Computer system 700 also includes a communication interface 718 coupledto bus 702. Communication interface 718 provides a two-way datacommunication coupling to a network link 720 that is connected to alocal network 722. For example, communication interface 718 may be anintegrated services digital network (ISDN) card, cable modem, satellitemodem, or a modem to provide a data communication connection to acorresponding type of telephone line. As another example, communicationinterface 718 may be a local area network (LAN) card to provide a datacommunication connection to a compatible LAN. Wireless links may also beimplemented. In any such implementation, communication interface 718sends and receives electrical, electromagnetic or optical signals thatcarry digital data streams representing various types of information.

Network link 720 typically provides data communication through one ormore networks to other data devices. For example, network link 720 mayprovide a connection through local network 722 to a host computer 724 orto data equipment operated by an Internet Service Provider (ISP) 726.ISP 726 in turn provides data communication services through the worldwide packet data communication network now commonly referred to as the“Internet” 728. Local network 722 and Internet 728 both use electrical,electromagnetic or optical signals that carry digital data streams. Thesignals through the various networks and the signals on network link 720and through communication interface 718, which carry the digital data toand from computer system 700, are example forms of transmission media.

Computer system 700 can send messages and receive data, includingprogram code, through the network(s), network link 720 and communicationinterface 718. In the Internet example, a server 730 might transmit arequested code for an application program through Internet 728, ISP 726,local network 722 and communication interface 718.

The received code may be executed by processor 704 as it is received,and/or stored in storage device 710, or other non-volatile storage forlater execution.

10. Equivalents, Extensions, Alternatives and Miscellaneous

In the foregoing specification, possible embodiments of the inventionhave been described with reference to numerous specific details that mayvary from implementation to implementation. Thus, the sole and exclusiveindicator of what is the invention, and is intended by the applicants tobe the invention, is the set of claims that issue from this application,in the specific form in which such claims issue, including anysubsequent correction. Any definitions expressly set forth herein forterms contained in such claims shall govern the meaning of such terms asused in the claims. Hence, no limitation, element, property, feature,advantage or attribute that is not expressly recited in a claim shouldlimit the scope of such claim in any way. The specification and drawingsare, accordingly, to be regarded in an illustrative rather than arestrictive sense.

What is claimed is:
 1. A light source comprising: a light guideconfigured to confine a first light within the light guide throughinternal reflection; a plurality of light extractors configured toextract at least a portion of the first light from the light guide uponestablishing at least one optical contact with the light guide; whereinthe light source is configured to move at least one of (a) individuallight extractors in the plurality of light extractors or (b) portions ofthe light guide to cause an optical contact between a light extractor inthe plurality of light extractors and a portion of the light guide.
 2. Amethod, comprising: confining first light within a light guide throughinternal reflection; extracting at least a portion of the first lightfrom the light guide upon establishing optical contacts between thelight guide and one or more light extractors in a plurality of lightextractors; wherein at least one of (a) individual light extractors inthe plurality of light extractors or (b) portions of the light guide isconfigured to be moved to cause an optical contact between a lightextractor in the plurality of light extractors and a portion of thelight guide.
 3. An apparatus comprising a processor and configured toperform the method recited in claim
 1. 4. A computer readable storagemedium, comprising software instructions, which when executed by one ormore processors cause performance of the methods recited in claim
 1. 5.A computing device comprising one or more processors and one or morestorage media storing a set of instructions which, when executed by theone or more processors, cause performance of the method recited in claim1.